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12.3 Training Northern Quolls to Avoid Eating Cane Toads 293

VetBooks.ir rejected them as prey, and consequently, the captive reared toad‐trained female quolls
successfully raised litters of young, and
trained quolls had higher survival than the
control group during the 10 day monitoring
revealed that the offspring of one of these
period (O’Donnell et al. 2010). Encouragingly, importantly, DNA analyses of parentage
several trained quolls that we reintroduced females also survived and reproduced
to Mary River Park, a tourist accommodation (Cremona et al. 2017b). Thus, some juvenile
site surrounded by monsoonal vine thicket quolls learnt to avoid eating cane toads, and
and savannah woodland, survived long term, social learning may be important in this
and one female survived to breeding age and respect. Quolls have a high degree of mater-
raised a family of quolls in the caravan park nal care, and the young often travel on their
owner’s machinery shed. mother’s backs at night. By radio‐tracking
These encouraging results suggested that it female quolls and their offspring, and plac-
might be possible to reintroduce ‘toad‐smart’ ing remotely triggered infrared cameras near
quolls to toad‐infested sites where northern the den sites of mothers when their offspring
quoll populations have crashed or gone were denning independently, we discovered
locally extinct. To test this idea, 50 captive‐ close associations between juveniles and
born quolls (28 males, 22 females) from the mothers. Notably, young quolls that were
Territory Wildlife Park were trained not to denning independently of their mother were
eat toads by feeding them a small (<2 g) dead photographed with their mother foraging at
toad coated with thiabendazole at a dose rate night (Figure 12.3), suggesting that juveniles
−1
of 300 mg kg predator mass. The quolls might have opportunities to learn what to
were released to suitable habitats (rock out- eat, and what not to eat, by observing their
crops) near East Alligator Ranger Station in ‘toad‐smart’ mothers hunting prey and sniff-
Kakadu National Park. Previous studies ing and rejecting toads as prey. Whether
showed that quolls were abundant at East such information is transmitted to offspring
Alligator prior to the arrival of cane toads, remains unknown, but seems likely (Galef
but the population crashed after toads and Laland 2005). Indeed, the extended
invaded and was on a path to extinction duration of maternal care in quolls provides
(Oakwood and Foster 2008; Woinarski et al. an opportunity for social learning in this
2010). The longer‐term survival of trained species. Alternatively, juvenile quolls might
‘toad‐smart’ quolls was monitored by trap- naturally learn to avoid eating toads by
ping three times each year (usually, in March, ingesting small non‐lethal sized toads that
May, and November) over four years. Tissue induce nausea and long‐lasting aversions in
samples were taken from all recaptured other small carnivorous marsupials (Webb
quolls, and DNA parentage analyses were et al. 2008, 2011).
run to determine the identity of the mothers Although for the second generation of
and fathers of juveniles in the population. quolls bred in the wild, the reintroduction
Monitoring of quolls revealed that toad was not successful. Even though cane toads
aversion training conferred long‐term bene- were no longer a major source of mortality
fits for some quolls. Most males disappeared for toad‐trained quolls, predation by free‐
from the study sites shortly after release, but ranging domesticated dogs and dingoes were
four males that were recaptured survived for major sources of mortality for quolls on the
an average five months (range 1–10 months). study site. Indeed, predation by canids is
Males typically only live for a year, so these probably preventing the reintroduced popu-
males survived long enough to breed with lation of quolls from recovering (Cremona
females. Females survived longer than males, et al. 2017). Unfortunately, the loss of tradi-
and seven females that were recaptured on tional burning practices in Kakadu has led to
the study site survived for an average of nine an increase in hot late dry season fires
months (range 2–22 months). Three of these (Russell‐Smith 2016); these fires incinerate